Error Code or Message on Panel
Modern washing machines are controlled by computer modules. Many of these contain their own fault diagnosis, and will be able to monitor certain aspects of the hardware. If one of the modules detects a fault in the equipment, or the module itself fails to respond to the main controller, the board will show an error message. This will be extremely meaningful to an engineer with a code book but not so much to the home user. Sometimes you can get the meaning of these codes from the manufacturer or their website. Often this is a closely guarded secret to ensure work for their engineers.
Demo/Test Mode
A common problem observed with modern washers is for them to go into demo mode (also sometimes shows as test mode). This is a mode designed for showrooms, and as most don't have plumbing will usually go to the spin cycle no matter what programme you put it on. This is usually inadvertently activated by a combination of button presses. The most common is pressing OK and Cancel (or equivalent buttons) at the same time. This same combination normally turn off the demo mode.